The processes known until now to obtain Zeolite 4A do not mention the bauxite as an aluminium source. The manufacture of Zeolite 4A starting from bauxite has several inconvenients in the crystallization step and in the color and purity of the final product, and also in the generation of contaminant residues. With the technology described in this invention, all these inconvenients are avoided, obtaining an optimum product for the manufacture of detergents. Moreover, the substitution of alumina trihydrate by bauxite, which is cheaper, and the possibility of its digestion at atmospheric pressure, notably reduces the manufacturing costs of Zeolite 4A.